Side tracking apparatus



Nov. 14, 1944. G. .'J. BARRETT ETAL SIDE TRACKING APFARATUS Filed Aug. so; 1940 4r w Mk n A W 0 2 H f mg m V md. A E N l ,6 w l E r l E s o 6 o y .f W Z 4 C I I Il L 2. l I 'Il Il Il Il Il. PPI. a b 7 8 6 0 TY 6 2 l v 3 4 5 n ,sm...sm?.\.nsn. .,9/

IIIIIIII Patented Nov. 14, 1944 SIDE TRACKINGAPPARATUS George J. Barrett and Sosthene Robicha'ux; Houston, Tex.; Rose Robishaw, executrix of l -A-l Bit land Tool Com a special partnership said Sosthene Robichaux; deceased, assignors to pany Ltd., Houston, Tex.,v

*Application August so, 1940, serial No. 354,816' 'ff 4 olaims.- (e1. 25E- 1.6) 'l Thisinvention'relates to side tracking apparatus. 'e v V e g An object of .theinven'tion is to provide apparatus of the character described specially de signed for forming' a side window in a well casing through whichfurther drilling operations may -be continued. l

In drilling wells it often happens that the well becomes obstructed so that drilling operations cannot be continued through the original well bore; or the original -bore may become deflected to such an extent that it becomes necessary to straighten the same. In either of such events a whipstock may be lowered into the well and oriented and anchored in place at the desired location and a milling tool then lowered into the well to co-act with the whipstock and whereby -a vertically elongated window may be formed through the side of the casing through which further drilling may Proceed.

It is another object of the present invention to provide apparatus embodying a novel type of whipstock for carrying on the side tracking operation hereinabove referred to.

The invention embodies a novel type of whipstock wherein the guide for the milling tool comprises antifriction roller bearings which will hold the milling tool against the work, this form of Ithe apparatus being specially designed for `forming a window in the casing either by milling the casing, if this can be done, or by shattering the side wall of casing which has 4become too hard to be milled out.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation and arr-angement of parts examples of which are given in this specification and illustrated in the accompanying drawing wherein- Figure l shows a fragmentary, vertical, sectional view of rthe whipstock showing the milling tool-in coo-peration therewith.

Figure 2 shows avertical sectional View showing the whipstock in elevation. e

Figure 3 shows a cross sectional View taken on the line 3 3 of Figure l, and

Figure 4 shows an enlarged, fragmentary, elevational View of the type of whipstock shown in Figures l and 2.

Referring now more particularly to the drawing wherein like numerals of reference designate the same yparts in each of the iigures, the numeral I designates a whipstock whose lower end is approximately cylindrical and which may be set in. the well casing 2 at any desired elevation'. When on vertical axes.

lowered to the .point where it is to beset it may be fixed in theca'sing against further downward movement in any conventional manner as shown,

' it is provided with arrlupwadly and outwardly t'a'- perin'fg' face 3" and an upwardly taperingV wedge shaped slip` #works against the face 3. Inthe present illustration a- 5- is attached to thel slip #and extends on dowfinto the well and is of a length to cause thevslip't'o set' at the desired elevation. When the whipstock is lowered untilthe lower end of the rod lands on bottom, it will then force the slip 4 upwardly relative to the whipstock and outwardly into engagement with the well casing. The slip has the external downwardly pitched teeth which will engage the casing and set the whipstock against downward movement during subsequent milling operations. The whipstock may be attached to the lower end of the milling tool as 6a which in turn is carried at the lower end of the drill stern 1. It may be so attached by means of a suitable shear pin as 8 and when it is let down into the well and set the pin may be sheared to allow the milling tool to move on downwardly as hereinafter explained.

The whipstock is provided with the upper and lower downwardly and outwardly tapering faces 8 and I0 which are spaced -apart to provide the vertical face II between them. These faces are arcuate in horizontal cross sectional contour.

It sometimes happensthat the casing 2 is so hard that it cannot be readily cut away by a mill in forming the window. Usually, however, the very hard casing can be broken so as to form a window therethrough. For this purpose a special type of whipstock and mill has been provided as shown in Figures 1 to 4, inclusive. Series of rollers II are mounted on the -vertical face I I of the whipstock. These rollers are mounted to rotate The mill Ga, to be'used in such case, has its lower face formed into an approximately inverted conical shaped guide 6b which engages against the inside of the casing, as shown in Figure 1. AS the work progresses, this mill operates against the casing as well as against the rollers I1 and as it moves downwardly it is wedged between said rollers and the casing and the weight of the drill stem above will cause it to crush the side of the casing against which it operates thus gradually forming an elongated window through the side of the casing.

The milling tool is provided with external cutting teeth, as shown, and the form of mill shown in Figure 1 will either shatter or cut away the' casing so as to effectively form an elongated window therethrough through which subsequent drilling operations may be carried on.

When the lower tapering face l0 has been reached by the milling tooll 6a, said tool is withdrawn and a special type of mill is then employed y Gil tool is lowered between said surface and the opy posing side of the casing and whereby the milling tool will be forced through said side of the i casing as the tool is lowered and rotated.

2. Inside tracking apparatus for wells, a whipstock shaped to enter a well casing, means for anchoring the whipstock to the casing, said whipstock having a longitudinal surface abovel the anchoring means and spaced from one side of the casing when the whipstock is in the casing, antifriction means arranged on said surface in position-to contact with a milling tool as said tool is lowered between said surface and the opposing side of the casing and whereby the milling tool will be forced through said side of the casing as the tool is lowered and rotated.

3. In side tracking apparatus for wells, a whip stock shaped to enter a well casing and adapted to force a milling tool through the side of said casing, said whip-stock having a lower downwardly and outwardly tapering face and an approximately vertical face above the tapering face and anti-friction rollers disposed along the vertical face of the whip stock approximately from end to end thereof.

4. Side tracking apparatus for wellscomprising a well casing, a milling tool, a stem for driving the tool, a, whip stock shaped to enter the well casing and adapted to force the milling tool through the side of said casing, said whip stock having upper and lower downwardly and outwardly tapering faces and an approximately vertical face between said tapering faces and rotatable, bearing means extending from the upper to the lower end of the vertical face of the whip stock and arranged to hold the milling tool in contact with the casing and out of contact with said vertical face.

GEORGE J. BARRETT. SOSTHENE ROBICHAUX. 

